re: U.S. invasion of Iran. Will it happen and who do you think would win?

Honestly, it would end up being like Vietnam if they did it tomorrow. The American People do not want to go into another war. Support would tank tremendously. Give it 10 years, and still it would probably not go. Unless Iran was taken under control of a murderous dictator, we wouldn't support it as a whole. Even then, I think we'd have a hell of a lot of support to the point it would not be just us in the dictator scenario.

re: U.S. invasion of Iran. Will it happen and who do you think would win?

Looking at those plans seems likely that the placement of US troops in both theaters was merely a staging point so we would have Iran surrounded. Honestly, America isn't in the proper economy to be taking on 3 wars at once considering we've not accomplished much in the ones we are currently in. Focusing more on Iran would basically mean removal from both Iraq and Afghanistan in turn bringing out the idea that the enemy has won allowing them tremendous boost in morale as well as increasing their political control ala more support from locals.

Tactically this is a very unsafe, un-smart costly decision if it were to become a reality.